Roehnelt, R.; Kassner, M.E.; Kennedy, T.C. & Rosen, R.S. Elastic incompatibility stresses across planar and nonplanar grain boundaries in silver, aluminum, and zirconium applied to ductile fracture criteria under high triaxial stress, report, July 1, 1996; (https://digital.library.unt.edu/ark:/67531/metadc683585/m1/1/: accessed April 25, 2019), University of North Texas Libraries, Digital Library, digital.library.unt.edu; .